A portable computer is a computer that is designed to be moved from one place to another and includes a display and keyboard. Portable computers, by their nature, are generally microcomputers.[1] Portable computers, because of their size, are also commonly known as 'Lunchbox' or 'Luggable' computers. They can also be called a 'Portable Workstation' or 'Portable PC'.

These are distinct from desktop replacement computers in that they are usually constructed from full-specification desktop components, and do not incorporate features associated with laptops or mobile devices. The principal advantage of a portable computer versus a laptop or other mobile computingdevice is the use of standard motherboards or backplanes providing plug-in slots for add-in cards. This allows mission specific cards such as test, A/D, or communication protocol (IEEE-488, 1553) to be installed. Portable computers also provide for more disk storage by using standard 3-1/2" drives and providing for multiple drives.

In 1973 the IBM Palo Alto Scientific Center developed a portable computer prototype called SCAMP (Special Computer APL Machine Portable) based on the IBM PALM processor with a Philips compact cassette drive, small CRT and full function keyboard. SCAMP emulated an IBM 1130 minicomputer in order to run APL\1130.[2] In 1973 APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP 9800 offered only BASIC. Because SCAMP was the first to emulate APL\1130 performance on a portable, single user computer, PC Magazine in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer".[3][4]

Successful demonstrations of the 1973 SCAMP prototype led to the first commercial IBM 5100 portable microcomputer launched in 1975. The product incorporated an IBM PALM processor, 5 inch CRT, full function keyboard and the ability to be programmed in both APL and BASIC for engineers, analysts, statisticians and other business problem-solvers. IBM referred to its PALM processor as a microprocessor, though they used that term to mean a processor that executes microcode to implement a higher-level instruction set, rather than its conventional definition of a complete processor on a single siliconintegrated circuit. In the late 1960s such a machine would have been nearly as large as two desks and would have weighed about half a ton.[5]

The MIT Suitcase Computer, constructed in 1975, was the first known microprocessor-based portable computer. It was based on the Motorola 6800. Constructed in a Samsonite suitcase approximately 20"x30"x8" and weighing approximately 20 lbs., it had 4K of SRAM, a serial port to accept downloaded software and connect to a modem, a keyboard and a 40-column thermal printer taken from a cash register. Built by student David Emberson in the MIT Digital Systems Laboratory as a thesis project, it never entered production. It is currently in the collection of Dr. Hoo-Min D. Toong.

An early portable computer was manufactured in 1979 by GM Research,[6] a small company in Santa Monica, California. The machine which was designed and patented by James Murez. It was called the Micro Star and later changed the name to The Small One. Although Xerox claims to have designed the first such system, the machine by Murez predated anything on the market or that had been documented in any publication at the time - hence the patent was issued. As early as 1979 the U.S. Government was contracting to purchase these machines. Other major customers included Sandia Labs, General Dynamics, BBN (featured on the cover of their annual report in 1980 as the C.A.T. system) and several dozen private individuals and companies around the world. In 1979, Adam Osborne viewed the machine along with several hundred other visitors at the first computer show that was sponsored by the IEEE Westec in Los Angeles. Later that year the machine was also shown at the first COMDEX show.

Portable computers have been increasing in popularity over the past decade, as they do not restrict the user in terms of mobility as a desktop computer would. Wireless access to the Internet, extended battery life and more comfortable ergonomics have been factors driving this increase in popularity. All-in-One PCs such as the iMac can also be considered portable computers and often have handles built into the case.

DYSEAC The Second Standards Electronic Automatic Computer. DYSEAC was a first-generation computer built by the National Bureau of Standards for the US Army Signal Corps. It was housed in a truck, making it one of the first portable computers (perhaps the first). It went into operation in April 1954.